Tax-time is soon upon us, and for millions of Americans that means buying TurboTax again. Fastest way to get it? Download from Intuit. Cheapest way to get it? Buy at Costco.

Not anymore. This year the fastest AND cheapest way is to download it from Amazon. Yes, Amazon entered the software download business, although initially the only available products are the different TurboTax flavors.

The traditional, box-sale page points to the download version, claiming you will “save time and money by downloading” software. Well, not quite. The downloadable version of each product is priced to match the boxed product+shipping charges. This is a missed opportunity, there are obvious savings from not having to manufacture, ship and store a tangible product, so they could afford to create financial incentives to move more customers to the download option. (Note: “they” means both Amazon and TurboTax maker Intuit, which also offers the box and download at identical prices.)

There’s one thing I really, really don’t like about this new Amazon service: before you can purchase anything, you need to download and install the “Amazon Downloader”, which in turn will download and install the actual product. Now, I don’t know about you, but I certainly am not buying software frequently enough to justify the need for a client, whatever benefits(?) this approach may offer. And of course once you install software, you know you’re in for a lifetime of endless updates…

If you ever need to download your purchased software again, it’s available under a new section called “Your Media Library.” As Mashable’s Adam Hirsch discovered, this is a lot more than just a listing of your digital purchases: you can list all purchases from Amazon and other sources, adding your items by simply scanning their barcode through your webcam, Amazon will convert and import the information automatically . There are a number of ways to share all this with friends, start discussions, tag items, subscribe to your friends’ collections via RSS, and follow what’s hot at any time.

If you think this is all similar to FaceBook’s Beacon, that’s because it is. With a significant difference: Amazon’s version is entirely opt-in.